In general, a single crystal ingot is grown using the Czochralski (CZ) crystal growth method. More particularly, the CZ crystal growth method includes loading a solid material, such as polycrystalline silicon, into a crucible disposed in a hot zone area, forming a melt by heating and melting the solid material using an electric heater, dipping a single crystal seed into the melt by holding the seed using a seed holder, and slowly raising the seed while rotating the seed. The seed holder raises a single crystal ingot in the sequence of a neck part, a shoulder part having an increasing diameter, and a body part having a constant diameter. Finally, the single crystal ingot is terminated at a tail part having a decreasing diameter.
An ingot growing apparatus for growing a single crystal ingot in the above-described method includes: a main chamber having a cooling means; a quartz crucible disposed within the main chamber to melt polycrystalline silicon (into a hot melt); a graphite crucible supporting the quartz crucible; a pedestal supporting the quartz crucible and the graphite crucible; an electric heater heating the crucibles; a power supply means for supplying a large amount of power to the electric heater; a driving shaft and a driving means for supporting, rotating, raising, and lowering the crucibles and the pedestal; a dome chamber disposed on top of the main chamber; a gate valve and a viewing port disposed on the dome chamber; a pull chamber disposed on top of the dome chamber; and an ingot-raising cable and an ingot-raising means (seed mechanism) disposed in the pull chamber.
The ingot growing apparatus may further include a vacuum means for maintaining the interior of the pull chamber, the dome chamber, and the main chamber in a vacuum state; a cooling means for cooling the ingot; a plurality of detecting means for detecting states required for the growth of an ingot; a control means for controlling the plurality of detecting means; a measuring means; and the like.
However, the ingot growing apparatus of the related art has neither a function of nor a means for measuring the weight of an ingot. Thus, the length of a growing ingot is measured as a method of calculating the weight of the growing ingot and the weight of the remaining melt during a process of ingot growth. When the length of the ingot reaches a set value or when the weight of the ingot and the weight of the remaining melt reach set values, the process must be stopped for measurement. When the process is stopped in this manner, a large amount of expensive melt may remain. Although the remaining melt can be re-melted and reused, the quality of the reused melt is significantly lowered, which is problematic.